Researchers short-circuit the immune system to block HIV

Researchers give mice lifelong protection against HIV, without the need for a …

So far, efforts to develop a vaccine against HIV have failed. It's not that they don't induce people to make antibodies against the virus—they make plenty of those—it's just that most of the antibodies don't usually keep the virus from infecting new cells. Nevertheless, these sorts of antibodies are possible to make. A number of patients that weren't vaccinated but fail to develop AIDS following HIV infection have been identified, and some of them are protected by antibodies that successfully neutralize many strains of HIV.

Since these broadly neutralizing antibodies are the sorts of things we want out of the vaccination process, a team of labs at Caltech and UCLA decided to short-circuit the need for a vaccination, or even antibody-producing immune cells. They created a disarmed adenovirus that contained the genes needed to produce a broadly effective antibody from humans, optimizing the DNA to make sure that the antibody was made in muscle cells, and then secreted into their environment.

The modified virus was then injected into mice that had had their immune systems humanized (the stem cells in their bone marrow were killed off and then repopulated with human cells). The mice were then exposed to levels of HIV many times higher than are normally present during initial infections. Not all antibodies effectively blocked new infections, but at least one did so consistently. The resistance to new HIV infections persisted for the life of the experiments.

The authors are clearly thinking that this isn't just a demonstration that will be limited to the lab, since they argue that "Our results suggest that successful translation of this approach to humans may produce effective prophylaxis against HIV." That translation may be challenging, however, as the use of these viruses in gene therapies has been somewhat mixed. Still, it seems like a promising idea, given that it could mean a one-time needle stick for lifelong protection.